/
main.go
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/
main.go
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package main
import (
"bytes"
"crypto/md5"
"encoding/hex"
"fmt"
"html/template"
"io/ioutil"
"log"
"net/http"
"net/url"
"time"
"github.com/gorilla/context"
"github.com/gorilla/schema"
"github.com/huandu/facebook"
"github.com/samertm/syncfbevents/conf"
"github.com/zenazn/goji"
"github.com/zenazn/goji/web"
"golang.org/x/oauth2"
facebookoauth "golang.org/x/oauth2/facebook"
)
var errorTemplate = initializeTemplate("templates/error.html")
type errorTemplateVars struct {
Code int
Message string
}
func initializeTemplate(file string) *template.Template {
return template.Must(template.ParseFiles("templates/layout.html", file))
}
var indexTemplate = initializeTemplate("templates/index.html")
type indexTemplateVars struct {
Name string
CalendarURL string
}
func serveIndex(c web.C, w http.ResponseWriter, r *http.Request) error {
s := getSession(c)
u := getUser(s) // SAMER: Change to auth.
v := indexTemplateVars{}
if u != nil {
v.Name = u.Name
// SAMER: Reverse router?
rawurl := absoluteURL(fmt.Sprintf("/calendar/%s?key=%s", u.FacebookID, u.SecretKey()))
calURL, err := url.Parse(rawurl)
if err != nil {
return err
}
calURL.Scheme = "webcal"
v.CalendarURL = calURL.String()
}
return indexTemplate.Execute(w, v)
}
func serveLogin(c web.C, w http.ResponseWriter, r *http.Request) error {
url := oauthConf.AuthCodeURL(oauthStateString, oauth2.AccessTypeOnline)
return HTTPRedirect{
To: url,
Code: http.StatusSeeOther,
}
}
func serveFacebookCallback(c web.C, w http.ResponseWriter, r *http.Request) error {
s := getSession(c)
state := r.FormValue("state")
if state != oauthStateString {
return fmt.Errorf("invalid oauth state, expected '%s', got '%s'\n", oauthStateString, state)
}
code := r.FormValue("code")
token, err := oauthConf.Exchange(oauth2.NoContext, code)
if err != nil {
return fmt.Errorf("oauthConf.Exchange() failed with '%s'\n", err)
}
// Save token here.
res, err := facebook.Get("/me", facebook.Params{
"access_token": token.AccessToken,
})
if err != nil {
return fmt.Errorf("fb.Get() failed with '%s'\n", err)
}
log.Printf("Logged in with Facebook user: %s\n", res["name"])
var v struct {
Name string `facebook:",required"`
ID string `facebook:",required"`
}
if err := res.Decode(&v); err != nil {
return err
}
// Save user to DB.
u, err := GetCreateUser(v.Name, v.ID)
if err != nil {
return fmt.Errorf("Could not create user %s: %s", res["name"], err)
}
// SAMER: Replace with fb.ExchangeToken.
// Get the longer lasting token.
var longLivedTokenURL = facebookoauth.Endpoint.TokenURL + "?" +
"grant_type=fb_exchange_token&" +
"client_id=" + oauthConf.ClientID + "&" +
"client_secret=" + oauthConf.ClientSecret + "&" +
"fb_exchange_token=" + token.AccessToken
resp, err := http.Get(longLivedTokenURL)
if err != nil {
return fmt.Errorf("Could not extend access token for %s: %s", v.Name, err)
}
b, _ := ioutil.ReadAll(resp.Body)
m, err := url.ParseQuery(string(b))
if err != nil {
return fmt.Errorf("Could not parse long-lived token for %s: %s", v.Name, err)
}
if len(m["access_token"]) == 0 || len(m["expires"]) == 0 {
return fmt.Errorf("Values missing from long-lived token response for %s: %s", v.Name, err)
}
if err := SetAccessToken(u, m["access_token"][0], m["expires"][0]); err != nil {
return fmt.Errorf("Could not set long-lived access token for %s: %s", v.Name, err)
}
s.Values[userIDSessionKey] = u.ID
if err := s.Save(r, w); err != nil {
log.Println(err)
}
return HTTPRedirect{To: "/", Code: http.StatusSeeOther}
}
type calendarQuery struct {
Key string `schema:"key"`
Raw bool `schema:"raw"`
}
// Handles "raw" query by spitting out raw Events list.
func serveCalendar(c web.C, w http.ResponseWriter, r *http.Request) error {
fbID := c.URLParams["fbID"]
u, err := GetUser(UserSpec{FacebookID: fbID})
if err != nil {
return err
}
var query calendarQuery
if err := schema.NewDecoder().Decode(&query, r.URL.Query()); err != nil {
return err
}
// Check that the user's secret key is valid.
if query.Key != u.SecretKey() {
return fmt.Errorf("User %d has invalid key for URL %q", u.ID, r.URL)
}
// Check to see if the user has a valid access token.
if !u.AccessToken.Valid || u.ExpiresOn == nil || u.ExpiresOn.Before(time.Now()) {
return fmt.Errorf("The access token for %d is not valid", u.ID)
}
fbSession := fb.Session(u.AccessToken.String)
res, err := fbSession.Get("/me/events?"+
"fields=owner,end_time,description,id,name,rsvp_status,"+
"place,start_time,timezone", nil)
if err != nil {
return fmt.Errorf("Could not get events: %s", err)
}
pr, err := res.Paging(fbSession)
if err != nil {
return fmt.Errorf("Could not use as paging result: %s", err)
}
var allEvents []Event
dateMarker := time.Now().Add(-48 * time.Hour)
outer:
for {
for _, r := range pr.Data() {
var e Event
if err := r.Decode(&e); err != nil {
return fmt.Errorf("Could not decode events: %s", err)
}
dt, err := parseFacebookDateTime(e.StartTime)
if err != nil {
return fmt.Errorf("Error during calendar generation: %s", err)
}
e.startTimeParsed = dt
if e.startTimeParsed.T.Before(dateMarker) {
break outer
}
if e.RSVPStatus == "attending" {
allEvents = append(allEvents, e)
}
}
if !pr.HasNext() {
break
}
pr.Next()
}
if query.Raw {
// The URL has the query "raw".
w.Write([]byte(fmt.Sprintf("%+v", allEvents)))
return nil
}
cal, err := generateICal(fbID, u.Name, allEvents)
if err != nil {
return fmt.Errorf("Error generating calendar for %s: %s", fbID, err)
}
w.Write(cal)
return nil
}
var privacyPolicyTemplate = initializeTemplate("templates/privacypolicy.html")
func servePrivacyPolicy(c web.C, w http.ResponseWriter, r *http.Request) error {
return privacyPolicyTemplate.Execute(w, nil)
}
// SAMER: Convert to CLRF at some point?
func generateICal(fbID, userName string, es []Event) ([]byte, error) {
buf := &bytes.Buffer{}
buf.WriteString(`BEGIN:VCALENDAR
PRODID:-//Sync Events//NONSGML Sync Events V1.0//EN
X-WR-CALNAME:` + userName + `'s Facebook Events -- Attending Only
VERSION:2.0
CALSCALE:GREGORIAN
METHOD:PUBLISH
`)
for _, e := range es {
// Remember: every line must end with \n.
buf.WriteString("BEGIN:VEVENT\n")
var owner string
if e.Owner.Name == "" {
owner = "No Owner"
} else {
owner = e.Owner.Name
}
buf.WriteString(fmt.Sprintf("ORGANIZER:CN=%s:MAILTO:noreply@facebookmail.com\n", owner))
iCalStart, iCalEnd, err := toICalDateTime(e.startTimeParsed, e.EndTime)
if err != nil {
return nil, err
}
buf.WriteString(fmt.Sprintf("DTSTART:%s\n", iCalStart))
buf.WriteString(fmt.Sprintf("DTEND:%s\n", iCalEnd))
// UID: Hash the facebook ID with the user's ID.
buf.WriteString(fmt.Sprintf("UID:%s\n", generateICalUID(fbID, e.ID)))
buf.WriteString(fmt.Sprintf("SUMMARY:%s\n", toICalText(e.Name)))
if e.Place.Name != "" {
buf.WriteString(fmt.Sprintf("LOCATION:%s\n", toICalText(e.Place.Name)))
}
buf.WriteString(fmt.Sprintf("URL:%s\n", e.FacebookURL()))
if e.Description != "" {
buf.WriteString("DESCRIPTION:")
var d = e.Description + "\n\n" + e.FacebookURL()
buf.Write(toICalTextLimited(d, 34))
buf.WriteRune('\n')
}
buf.WriteString("CLASS:PUBLIC\n")
buf.WriteString("STATUS:CONFIRMED\n")
buf.WriteString("PARTSTAT:ACCEPTED\n")
buf.WriteString("END:VEVENT\n")
}
buf.WriteString("END:VCALENDAR\n")
return buf.Bytes(), nil
}
func generateICalUID(fbID, eventID string) string {
hasher := md5.New()
hasher.Write([]byte(fbID))
hasher.Write([]byte(eventID))
return hex.EncodeToString(hasher.Sum(nil)) + "@syncfbevents.com"
}
var FacebookDateTimeLayout = "2006-01-02T15:04:05-0700"
var FacebookDateTimeLayoutAlt = "2006-01-02T15:04:05" // Used pre-2013.
var FacebookDateLayout = "2006-01-02"
var ICalDateTimeLayout = "20060102T150405Z"
var ICalDateLayout = "20060102"
type DateTime struct {
T time.Time
DateOnly bool
}
func parseFacebookDateTime(datetime string) (DateTime, error) {
// First, we try to parse the startTime with a date and time.
dt, err := time.Parse(FacebookDateTimeLayout, datetime)
if err != nil {
// The date may be in the alternate format.
dtAlt, err := time.Parse(FacebookDateTimeLayoutAlt, datetime)
if err != nil {
// The date may be in the date layout.
d, err := time.Parse(FacebookDateLayout, datetime)
if err != nil {
return DateTime{}, fmt.Errorf("Could not parse datetime %s: %s", datetime, err)
}
return DateTime{T: d, DateOnly: true}, nil
}
return DateTime{T: dtAlt, DateOnly: false}, nil
}
return DateTime{T: dt, DateOnly: false}, nil
}
// startTime must be 2006-01-02 or 2006-01-02T15:04:05-0700. endTime
// must be in a similar format or empty. Returns a time string in a
// valid ICal UTC Date-Time format.
//
// If endTime is empty, then iCalEnd is one day after iCalStart if
// iCalStart does not include a time, otherwise it is set to three
// hours after iCalStart.
func toICalDateTime(startDateTime DateTime, endTime string) (iCalStart, iCalEnd string, err error) {
if startDateTime.DateOnly {
d := startDateTime.T
// d is valid, format it as just a date.
iCalStart = d.UTC().Format(ICalDateLayout)
if endTime == "" {
// iCalEnd needs to be a day after iCalStart.
iCalEnd = d.UTC().Add(24 * time.Hour).Format(ICalDateLayout)
return iCalStart, iCalEnd, nil
}
// endTime is nonempty.
endD, err := parseFacebookDateTime(endTime)
if err != nil {
return "", "", fmt.Errorf("Error parsing endTime (%s): %s", endTime, err)
}
// iCalEnd must be the same value type as iCalStart,
// i.e. only a date.
iCalEnd = endD.T.UTC().Format(ICalDateLayout)
return iCalStart, iCalEnd, nil
}
dt := startDateTime.T
// dt is valid, format it as a date and time.
iCalStart = dt.UTC().Format(ICalDateTimeLayout)
if endTime == "" {
// iCalEnd needs to be three hours after iCalStart.
iCalEnd = dt.UTC().Add(3 * time.Hour).Format(ICalDateTimeLayout)
return iCalStart, iCalEnd, nil
}
// endTime is nonempty, and must have the same value type as
// startTime, i.e. a date-time.
endDT, err := parseFacebookDateTime(endTime)
if err != nil {
return "", "", fmt.Errorf("Error parsing endTime (%s): %s", endTime, err)
}
iCalEnd = endDT.T.UTC().Format(ICalDateTimeLayout)
return iCalStart, iCalEnd, nil
}
// Convert text to iCal-prepared text.
// text = *(TSAFE-CHAR / ":" / DQUOTE / ESCAPED-CHAR)
// ; Folded according to description above
//
// ESCAPED-CHAR = ("\\" / "\;" / "\," / "\N" / "\n")
// ; \\ encodes \, \N or \n encodes newline
// ; \; encodes ;, \, encodes ,
//
// TSAFE-CHAR = WSP / %x21 / %x23-2B / %x2D-39 / %x3C-5B /
// %x5D-7E / NON-US-ASCII
// ; Any character except CONTROLs not needed by the current
// ; character set, DQUOTE, ";", ":", "\", ","
func toICalText(text string) []byte {
return toICalTextLimited(text, 0)
}
// toICalTextLimited returns an iCal-prepared text. If lineLength is 0
// or less, the lines are not limited. Otherwise, lines are limited to
// around lineLength.
func toICalTextLimited(text string, lineLength int) []byte {
var lines [][]byte
buf := &bytes.Buffer{}
for _, rune := range text {
// Check for escaped characters.
switch rune {
case '\\':
buf.WriteString("\\\\")
case ';':
buf.WriteString("\\;")
case ',':
buf.WriteString("\\,")
case '\n':
buf.WriteString("\\n")
default:
buf.WriteRune(rune)
}
if lineLength > 0 && buf.Len() >= lineLength {
// Flush buf and wipe.
lines = append(lines, buf.Bytes())
buf = &bytes.Buffer{}
}
}
if buf.Len() != 0 { // SAMER: I think I need this.
lines = append(lines, buf.Bytes())
}
return bytes.Join(lines, []byte("\n "))
}
type Event struct {
ID string `facebook:"id,required"`
Name string `facebook:"name,required"`
StartTime string `facebook:"start_time,required"`
EndTime string `facebook:"end_time"`
RSVPStatus string `facebook:"rsvp_status"`
Description string `facebook:"description"`
Owner EventOwner `facebook:"owner"`
Place EventPlace `facebook:"place"`
startTimeParsed DateTime // Does not exist in Facebook's output.
}
func (e Event) FacebookURL() string {
return fmt.Sprintf("https://www.facebook.com/events/%s/", e.ID)
}
type EventOwner struct {
Name string `facebook:"name"`
}
type EventPlace struct {
Name string `facebook:"name"`
}
var (
oauthConf = &oauth2.Config{
ClientID: conf.Config.FacebookID,
ClientSecret: conf.Config.FacebookSecret,
RedirectURL: conf.Config.BaseURL + "/facebook_callback",
Scopes: []string{"user_events"},
Endpoint: facebookoauth.Endpoint,
}
oauthStateString = conf.Config.OAuthStateString
fb = facebook.New(conf.Config.FacebookID, conf.Config.FacebookSecret)
)
func main() {
// Serve static files.
staticDirs := []string{"bower_components", "res"}
for _, d := range staticDirs {
static := web.New()
pattern, prefix := fmt.Sprintf("/%s/*", d), fmt.Sprintf("/%s/", d)
static.Get(pattern, http.StripPrefix(prefix, http.FileServer(http.Dir(d))))
http.Handle(prefix, static)
}
goji.Use(applySessions)
goji.Use(context.ClearHandler)
goji.Get("/", handler(serveIndex))
goji.Get("/login", handler(serveLogin))
goji.Get("/facebook_callback", handler(serveFacebookCallback))
goji.Get("/calendar/:fbID", handler(serveCalendar))
goji.Get("/privacypolicy", handler(servePrivacyPolicy))
goji.Get("/privacypolicy.html", handler(servePrivacyPolicy))
goji.Serve()
}